u/Peabody66

[Emerald] Pokémon Gengar Edition — Gastly starter QoL hack, IPS + Python save editor on GitHub

[Emerald] Pokémon Gengar Edition — Gastly starter QoL hack, IPS + Python save editor on GitHub

Small weekend project I just finished and figured I'd share. It's a QoL

pack for Pokémon Emerald (US 1.0) focused on letting Gastly actually work

as a starter — which it canonically can't, because Ghost moves don't hit

Normal types and Gengar's evolution requires trading.

**What's in it:**

- Gastly replaces Treecko in Birch's satchel

- Haunter evolves into Gengar at level 36 — no trade needed

- Gastly's line gets a 36-move natural learnset from level 1 to 99,

including Bite at L1 (so it can actually damage Zigzagoon — yes I had

to fix this after the first playtest), plus Hypnosis, Sludge Bomb,

Shadow Ball, Psychic, Dream Eater, all three elemental punches,

Destiny Bond, Perish Song, Explosion, etc.

- All TMs and HMs are learnable by the Gastly line (HM Cut on a Ghost,

yes)

- HMs can be forgotten at the regular move menu — no Lilycove trip

- The other three starters are catchable in the wild at ~10% rate on

themed routes (Mudkip/Route 102, Torchic/Fiery Path, Treecko/Route 119)

- Mew (Route 120), Celebi (Petalburg Woods), and Deoxys (Route 121)

catchable at 1% rate

- Every Pokémon's catch rate is set to engine max (255). Not literally

100% with any ball, but very close when weakened — and Master Balls

remain Master Balls

- Gengar base stats boosted to pseudo-legendary tier (695 BST)

- Starting money is $999,999

**What's not in it (use community IPS patches on top):**

- Run Indoors

- Faster default text speed

- True 100%-catch-with-any-ball (needs the shake-formula patch)

- Title screen replacement — I made a mockup as reference art but the

actual tile-art conversion needs proper tools

**Tools / source:**

The repo also includes a native Python save editor (`gengar_save_editor.py`)

that handles nature and held-item edits. Runs on macOS/Linux out of the

box — no Wine, no .NET, no PKHEX required. Useful if you want a Timid

Gastly + Leftovers without PKHEX.

There's also a full technical write-up (`docs/hack_guide.md`) with every

byte offset documented, in case anyone wants to extend or modify.

**Built with Claude (Anthropic):** I drove design and playtesting, found

the bugs, made the decisions. Claude did the byte-level ROM work. Calling

that out up front because it'll come up otherwise. The Python save editor

was iteratively built and debugged the same way (it caught a substructure

re-ordering bug during testing).

**Repo:** https://github.com/apeabody007/Pokemon-Gengar-Edition-Emerald-Hack-

Verified against Pokémon Emerald US 1.0, CRC32 `1F1C08FB`. No ROM

included — just the IPS patch and tools. Apply to your own clean copy.

Happy to hear feedback, especially on the wild encounter placements and

the early-game learnset balance. Have fun.

u/Peabody66 — 1 day ago